“But what is racist?” she asked an all-white panel on Monday during a discussion about a university crackdown on offensive costumes.

“Because you do get in trouble if you are a white person who puts on blackface on Halloween, or a black person who puts on whiteface for Halloween. Back when I was a kid that was OK, as long as you were dressing up as, like, a character.”

She then defended a reality television show star who drew ire last year for darkening her skin and donning an afro wig to dress as Diana Ross.

“Who doesn’t love Diana Ross? She wants to look like Diana Ross for one day? I don’t know how that got racist on Halloween,” Kelly said.

The backlash was immediate – and the anchor was accused of being tone deaf and ignorant to racial sensitivities.

Incredulous viewers shared videos of the segment on social media, pointing out the well-known history of degrading depictions of African-Americans using blackface throughout US history.

Kelly apologised to NBC staff internally and then publicly to viewers on the Wednesday edition of her show.

But questions are being asked about whether the career of one of the country’s highest paid news stars can, or should, recover.

Kelly joined Fox News in 2004, with little previous experience as a reporter.

Born in 1970 in upstate New York, Kelly was the youngest of three children of a college professor father and a mother who worked as a nurse at a veteran’s hospital.

A keen cheerleader in high-school, she went on to study political science at Syracuse University before qualifying as a lawyer in Albany and practicing as an associate in a law firm for about a decade.

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Kelly, one of America’s best paid anchors, has sat down with Russian President Vladimir Putin twice

She then decided to switch careers and made a demo tape that got her work as a reporter for a local ABC affiliate in Washington DC, before bagging a job at Fox News about a year later.

In 2010 Kelly got her first solo spot presenting Fox’s America Live. She was credited by the network’s then head Roger Ailes for improving ratings, especially among younger audiences.

She was known for her unique and tough interviewing style, upper-cutting guests with a sharp line of questioning that would often leave them scrambling for a response.

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Kelly was with Fox News for more than a decade

As an anchor she courted controversy, especially from the left, with her coverage. In 2013 she made headlines after declaring Santa Claus had to be depicted as a white man.

“And by the way, for all you kids watching at home, Santa just is white,” Kelly said on the show. “Jesus was a white man, too… He was a historical figure, that’s a verifiable fact, as is Santa. I just want the kids watching to know that.”

Her other NBC slot, Sunday Night with Megyn Kelly, only aired eight times and has not been broadcast since July 2017.

The new row has led to previous comments she made when covering racially charged topics at Fox being brought back up, including one report where she described black communities of having an “anti-cop…thug mentality”.